This blog is dedicated to bringing World War II era documents to the general public, with an overall focus on armoured warfare.
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Monday, 29 February 2016

Bulletproof glass blocks are rectangular parallelepipeds, 82-84 mm tall, composed from steeled plates of cast polished reflective 1st category glass or non-steeled plates from the same glass. On a special order, the blocks can be made from barium sulphate glass.

The plates are glued together with synthetic resin created by NII-6.

The block is installed in a steel container produced according to technical requirements for steel containers, attached to these technical requirements.

The gaps between the block and the container are filled with Portland cement according to blueprint #101 and 56-162 (attached).

2. Purpose

The blocks are designed to be used in observation devices of fighting vehicles to protect the observer from armour piercing and regular bullets.

3. Technical Requirements

The light transmission of the block needs to be no less than 65% for regular glass and no less than 80% for barium sulphate glass.

During inspection with the unaided eye, under sunlight or artificial light, the block must have none of the following within 150 mm of the viewer's eye:

Harsh mechanical scratches

Thick string or knotted casting defects

Cracks

Cloudiness

Layering

Chips on the end of the plate wider than 7 mmIf one of the aforementioned defects is discovered, the block is defective.NOTE: The non-working part of the block is the part between the case and the surface connecting the frames of the rear and bullet-facing parts of the block. The rest of the block is the working part.

It is acceptable to have the following in the working part:

Bubbles no more than 0.75 mm in diameter (6) and no more than 0.5 mm in diameter (10) scattered throughout the block. No more than two bubbles on the internal or external surface.

An air bubble no more than 1 mm in diameter that is no more than 10 mm from the viewport frame. Conditions for bubbles 1 and 2 apply to the glass, as well as the resin.

Thin string-like defects with surface area of up to 1 mm or small defects visible by unaided eye by shining a light through the block, with the condition that the defects do not impede light transmission and do not cause distortion.

No more than 5 hair thin scratches up to 25 mm long.

Light internal mechanical scratches up to 3 mm long or one scratch up to 10 mm long, no more than 10 mm from the frame.

Light mattness that does not interfere with light transmission.

Light scratches on the front and rear that do not impede vision.

It is acceptable to have the following in the non-working part:

Hair-thin or mechanical scratches

Scratch or knot defects

Bubbles up to 2 mm in diameter, as well as bubbles in the resin up to 2 mm in diameter.

A matte spot on the side of the case caused by the case vice is acceptable no more than 10 mm from the edge of the cap.

Both vision surfaces of the block need to be parallel. The difference in block thickness needs to be no more than 0.5 mm, and the size must be at least what is specified in the blueprint.

4. Trial methods

2% of the blocks are taken by the BTU military representative for lab trials, and 4% of the blocks are taken for ballistics trials.Blocks for the the military representative must be provided no less than 3 days after the cement was poured. The military representative receives lab results from the factory laboratory in writing.

Blocks are subjected to the following trials:

Moisture tests: the block is submerged in a bath of distilled water at 15-20 degrees for 10 hours. The resin must hold.

Heat tests: the block is heated to 60 degrees for 30 hours. The resin must not lose hold leak out of the case.

Light transmission tests: Using a selenium photodiode or a Lummer-Bratkun bench. Light transmission must be no less than 65% for regular glass and no less than 80% for barium sulphate glass.

Distortion tests: a white screen with a 0.5 mm thick mesh in 10x10 mm cells is photographed. No distortions in the photograph are acceptable.

Ballistics tests: the block is fired upon with a 7.62 mm B-30 armour piercing bullet at 50 meters at normal, or with a regular VL bullet. The block must be installed in its steel case, filled with cement, and affixed in a turret. Only shots that do not touch the armour or frame count. Ballistics tests must be performed with the military representative present.After being hit with an armour piercing B-30 bullet or a regular bullet, the rear surface of the block must be whole and have no cracks or fragmentation.The results of the test are recorded in an act which is signed by the BTU representative and factory representative.

5. Rules of Quality Assurance

Blocks accepted by the factory are provided to the military representative with a seal indicating the day, month, and ear of production, as well as the batch number.The batch must be no less than 200 units, with the exception of situations where a smaller batch was ordered.

2% of the blocks are extracted for light, moisture, heat, and distortion tests, no less than 4 units.2% of the blocks are extracted for tests with B-30 armour piercing bullets and 2% of the blocks are extracted for tests with VL bullets.The muzzle velocity of the bullets are:

840-855 m/s with the regular sharp-tipped bullet.

795-810 m/s with the armour piercing bullet.Blocks are tested with bullets that have an expiry date stated in the manifest. It is acceptable to have a deviation of up to 10 m/s from an average of 10 bullets from the batch. Test muzzle velocity every three months with a chronograph.

If the blocks fail one or more of the aforementioned trials, secondary trials are held where twice as many blocks are extracted from the batch. Secondary trials only repeat the tests that were failed in initial trials. If the blocks fail trials again, the entire batch is considered defective. Each accepted block is sealed with the military representative's seal and the factory QA department's seal.

At a temperature of 16-23 degrees and a humidity of 70%, a block can be stored for 3 years. If a block becomes defective before that time, the factory must replace it at its own cost, except in the event of mechanical damage during use or storage.

Each shipped block is accompanied with a protective glass and instructions for storage and handling. The warranty period of the protective glass at a temperature of 16-23 degrees and humidity of 70% is 6 months.

Use 1941 production blocks as samples for acceptance testing.

6. Storage, packaging, and shipment

Blocks that have been accepted by the military representative are wrapped in paper.

Blocks must be stored at 16-23 degrees at 70% humidity.

For shipment, blocks wrapped in paper are packed in crates. Soft dry wood shavings are tightly packed in between the rows of blocks and between blocks and the crate to protect the blocks during handling.

No more than 30 blocks should be placed in one crate.

Each shipment of blocks should include a manifest placed in one of the crates containing the name of the items, amount, crate numbers, name of the factory director, plant foreman, packer and military representative, instructions for storage, service, and handling, and expiration date.

Sunday, 28 February 2016

The story of Britain's most powerful tank destroyer began in late January of 1951, when it was decided to develop a tank destroyer even more powerful than the FV4004 Conway, armed with a 120 mm L1A1 gun. It was destined to become the most powerful tank destroyer ever built. According to the requirements, it had to confidently penetrate a target with 150 mm of armour at 60 degrees from almost two kilometers away. This target was based on the IS-3. After appearing at the Victory Parade in 1945, this tank was considered the most dangerous opponent of Western tanks for decades.

Anti-IS QF L4 gun and its variants
In order to meet these requirements, the designers had to find a much more powerful gun than the L1A1. The British didn't bother with the small stuff and went right up to a caliber of 7.2 inches (183 mm). Using such a powerful caliber was no accident. This new gun was based on the 183 mm BL 7.2 inch Howitzer, which dates back to WWI. Initially, the howitzer had a barrel length of 22.4 calibers, but this was extended to 33.1 calibers. Unfortunately, even this extension was not enough to fight Soviet tanks.

In 1950, work started on the QF L4 gun, the most powerful tank gun in the world. The gun weighed a little under 4 tons and had nearly 87 tons of recoil force. In order to clear the fighting compartment of propellant fumes, the gun had a fume extractor fitted. Only one type of shell was planned for this gun: HESH (High Explosive Squashed Head). Not only is the caliber of the L4 stunning, but also the weight of the rounds. The propellant was separate from the shell, but this didn't make the loader's job much easier: the mass of the shell was 72 kg, and the mass of the propellant was 32.8 kg.

On November 9th, 1950, the War Office held a meeting to determine what vehicle this super-powerful gun would be placed on. The meeting resulted in four variants:

A fully armoured fighting machine (effectively a tank) with a fully rotating turret.

An SPG with powerful front armour, but a limited traverse angle.

An SPG with a fully rotating turret, but thin armour.

An SPG without armour.

Variant 1/2: FV215

The contract to develop the first variant went to Morris and was later transferred to Vickers-Armstrong. The chassis of the heavy FV200 tank was used, with the suspension from the heavy FV214 Conqueror tank. The project had multiple names: Heavy Gun Tank No.2, Heavy Anti-Tank SP No.2, FV215 Heavy Anti-Tank SP No.2 or simply FV215. The index Heavy Gun Tank No.2 was incorrectly interpreted by historians, resulting in a mythical project called FV215B. In reality, all these indices pointed to the same vehicle armed with the 183 mm L4 gun.

This project combined the first and second variants. Theoretically, the turret could rotate fully, but the gun was limited to firing within a 90 degree arc. The turret was placed in the rear in order to prevent the huge barrel from sticking out too far. The ammunition capacity was only 20 shells. The rate of fire of the tank was supposed to reach 6 RPM. but whoever set that requirement was a hopeless optimist. The size of the turret did not allow for a loading mechanism, and loading that quickly by hand was not possible. Aside from the gun, the tank had two machineguns: one coaxial and one AA machinegun on top of the turret.

The 65 ton vehicle was supposed to accelerate to 31.7 kph. In order to achieve this, the tank would have an 810 hp Meteor Mk.12 engine. As for the armour, it kept changing throughout the development process. The thickness of the upper front plate varied between 125 and 152 mm, the sides were 50 mm thick (plus spaced armour). As for the turret, the specification was only for the front, which was 254 mm (10 inches) thick.

The FV215 Heavy Anti-Tank SP No.2 was not meant to be. Morris was supposed to first build a full scale model and then two prototypes: one for mobility trials and one as a target for armour testing. In June of 1954, Vickers-Armstrong, the new owner of the contract, was given the same task. Development of the SPG continued until January of 1957. At that point, the full scale model and 80% of the blueprints were ready. But, the War Office got its own Khrushchev and the development of the FV215 Heavy Anti-Tank SP No.2 was shut down in favour of ATGMs.

Variant 4: FV4005 Stage I

As for the main subject of this article, the FV4005, work on it started a while later. Interestingly enough, the third variant was rejected outright, and designers went to the unarmoured option. This is linked to the fact that the required rate of fire of 6 RPM was unattainable without a loading mechanism. Vickers-Armstrong decided to not reinvent the wheel and use a loading system similar to the one on the 104 mm QF 127/58 SBT X1 AA gun, better known as Green Mace. The SPG with a 183 mm gun and an autoloader was known as FV4005 Stage I. An altered chassis of the Centution Mk.3 served as the base for the design. A huge trail was added to the rear, lowered during firing, and the front plate received a travel lock for the gun.

After trials that primarily tested stability of the vehicle wile firing, this design was rejected. It was decided that an SPG of this size that was completely devoid of armour was excessive, and even an automatic loader doesn't make it worth putting crewmen at such a risk. The fully rotating turret was also rather deceptive, as the powerful recoil limited the firing angle of the gun.

Variant 3: FV4005 Stage II

In July of 1955, specifications for a simpler 183 mm SPG were developed, the FV4005 Stage II. The massive automatic loader was discarded, replaced with two loader crewmen. Since even this variant couldn't carry more than 12 shells, this solution was considered acceptable. The vehicle received a massive turret. The height of the 50 ton SPG was 3.6 meters, making it the tallest vehicle built in Britain.

The turret armour was only 14 mm thick, meaning that it couldn't reliably protect the crew from even a high caliber machinegun. On the other hand, it was better than nothing. The Stage II also had a coaxial machinegun, which improved its chances against enemy infantry. A large turret was added to the rear of the turret to load ammunition. The creators of the FV4005 Stage II designed a system to rapidly supply ammunition from trucks, which somewhat compensated for the small ammunition capacity. The new turret was still installed on the Centurion Mk.3 chassis with a trail and a travel lock for the gun.

In March of 1956, the FV4005 Stage II underwent trials to determine the stability of the vehicle when shooting. 32 shots were made at various elevations in the first round. At an elevation of 0 degrees, the front of the vehicle moved up to 22 cm, and the rear up to 12 cm. The greatest oscillations were reached at an angle of 3 degrees, when the front moved up to 27 cm and the rear up to 19 cm. The trials were performed without a crew, who were replaced by mannequins. The trials showed that shooting does not injure the crew.

As a result of the trials, a list of improvements was composed, futilely. In August of 1957, the FV4005 program was closed. Various theories exist for why the super-powerful tank destroyer program was shut down. In reality, the reason was the same as with the FV215 Heavy Anti-Tank SP No.2. In 1958, the British army received Malkara ATGMs on light Humber Hornet cars. The system was much more compact and mobile, making the 183 mm SPG a relic of the past.

After completion of the trials, both FV4005 prototypes were disassembled. The Centurion Mk.3 hulls were used for other programs and the gun systems ended up in training facilities. The turret of the Stage II spent a lot of time in storage near the Bovington Tank Museum, and was only recently installed on a Centurion Mk.8 chassis. Even in this form, it is of great interest, serving as a epitaph for British tank destroyers. The FV4005 Stage II stands near the eastern entrance to the museum. Perhaps someday there will be funding to move it indoors and restore it.

Saturday, 27 February 2016

At the end of the 19th century, the United States of America began a sharp rise in the development of industry, science, education, and culture. The army and navy guaranteed protection from any opponent in the New World, and the oceans around North America acted as the most effective border guard against any transoceanic enemy.

Externally, the US practiced isolationist policies and kept far away from the wars that engulfed Europe. However, when WWI started, the situation changed. After a series of incidents that resulted in losses of American merchant vessels, President Wilson asked Congress to enter the war. On April 4th, 1917, the Senate allowed the United States to join the First World War.

On June 13th, 1917, General John Joseph Pershing and the first American expeditionary force arrived in Europe. This commander previously fought in local conflicts with the Apache and Sioux, in the Hispano-American War of 1898, and Pancho Villa's rebels. The positional war in Europe was somewhat different from what the American military imagined it to be, and Pershing understood the importance of an army that could deliver a powerful strike while remaining mobile. It is not surprising that he initiated the creation of armoured forces in the United States.

On January 26th, 1918, the American Tank Corps formed from two parts: the tank corps of the American Expeditionary Force in Europe and the Tank Force of the National Army, later renamed the Tank Corps of the National Army.

Proposals for armoured vehicles were sent to the American army before. In 1915, a businessman named Lowe proposed a 30 ton tank project based on the Willoc tractor. In 1917, the Holt tractor company proposed a vehicle that looked very similar to the British "Little Willie" tank, created by William Tritton.

Another interesting project was proposed by the Pioneer tractor company in Minnesota. The vehicle was nicknamed "Skeleton", due to its suspension. The tracks of the Skeleton were not attached to the hull, but to a metal frame with pipe connectors. A small rectangular hull, designed for two crew members, was located between these frames.

The military's lack of enthusiasm towards American tanks led to the necessity of purchasing foreign vehicle when General Pershing ordered the creation of a tank force. On September 12th, 1918, the American tankers fought their first battle at Saint-Michelle, a village south of Verdun. Lieutenant-Colonel Patton commanded the 344th and 345th tank battalions in this battle.

American armoured doctrine used small, light, medium, and heavy tanks. The battle-proven French Renault FT-17 was chosen as the light tank. This 6-ton vehicle was one of the most advanced in the world. The layout of the FT-17 was later accepted as classical: the armament was located in a rotating turret, engine in the rear, crew compartment up front. Initially, the Americans planned to order 3500 vehicles of this type. Some of these were to be built by the French, and some by the Americans. The Ford company purchased a license to manufacture these tanks.

American engineers altered the design of the tank. The driver's visibility was improved. Armour was increased. The Renault engine was replaced with an American one. The American version of the FT-17 was indexed M1917. The tank was armed with either a 37 mm gun or a machine gun.

Heavy tank units were to be armed with the jointly developed British-American Mark VIII Liberty tanks. This tank was a typical "rhombus" type, with fairly wide tracks, enclosing the entire hull. The vehicle weighed 39 tons, and was armed with two 57 mm Hotchkiss guns, with 5-7 rifle caliber machine guns for support. The 10-meter long tank was crewed by 8-11 people

The Liberty was the peak of British rhombus tanks. Perhaps, this direction could be developed further, but, as soon as the FT-17 was deemed superior, the time of the rhombus came to an end.

The Mk VIII did not fight in WWI. The Americans built about 100 of these vehicles in 1919-1920. Until 1930, it remained America's only heavy tank.

After WWI ended, large tank units proved too expensive for the USA, and, in 1920, the tank corps was disbanded. Over the next 20 years, the US did not have large tank units, but funding was periodically issued for new vehicles.

For examples, in the 1920s, the army staff considered the M1917 obsolete, and initiated the construction of a new light tank. Specialists from the Rock Island Arsenal, along with engineers from the Cunningham tractor company, presented the T1 project in 1924. This small 7-ton tank had a non-standard layout, with a rear turret, and front engine. The tank was armed with a 37 mm cannon and 7.62 mm machine gun. Numerous modifications of the T1 project were developed over its lifetime, but they all had their flaws, and were rejected.

The last of the Cunninghams, the T1E4 and T1E6, were meant to solve the flaws of their predecessors. Elements of the British Vickers 6-ton were used in their construction. The engineers achieved superior mobility with the same armament, but there were serious problems with the gearbox and the tanks were not mass produced.

The Americans designed new light tanks for seven years after the termination of the Cunningham program. One of these tanks was the T2 Light on a Vickers suspension. It was designed with machine guns and small caliber autocannons for armament. The T2 was not mass produced, but its creation led to valuable experience, leading to a mass produced M2 Light tank with a new suspension and machine gun armament. On December 29th, 1938, the Americans accepted and began production of a new M2A4 light tank. This tank was armed with a cannon. The new vehicle was maneuverable, and had armour comparable with American medium tanks of the time. Mass production of the M2A4, in which the Americans experimented with cast hulls and turrets, never got off the ground. Welding and riveting of armour continued until the spring of 1941.

In parallel with the T1 tanks, the Americans were developing a medium tank, superior to the Liberty in mobility, and to light tanks in protection. The new tank would have been indexed M1921. It weighed 23 tons, and was armed with a 75 mm howitzer in a rotating turret. This howitzer was capable of not only immobilizing, but completely destroying, a light tank with a direct hit. This was demonstrated practically, using poor M1917 tanks as targets. After 7 years of development, the vehicle was not mass produced due to high cost.

In parallel with the T1 Medium, another lighter medium tank was developed, the T2 Medium. It was built by the Cunningham company using the same layout as the light T1. The tank could accelerate up to 25 mph, and was armed with a 37 mm or 47 mm gun, and machine guns. The T2 Medium was the best tank developed by the Bureau of Ordnance. And yet, it was too expensive for an America that was struggling with the Great Depression.

The Great Depression led to a reconsideration of many principles of armoured warfare. Tank units were to be armed with light, mobile, and cheap vehicles. Engineer Christie proposed some projects, but the military's response to his convertible designs was rather unenthusiastic.

By 1934, Christie annoyed the military so much, that they were ready to accept anything, as long as they didn't have to deal with the persistent and rude engineer. In April of 1934, Captail Reiry proposed a tank project using the Christie chassis and 4 machine gun sponsons, along with a 37 mm gun in a rotating turret. The Bureau took the opportunity to reject the Christie suspension, and instead take a recently developed suspension unified with the T2 Light tank. The resulting vehicle was indexed T5.

After many modifications, the tank was built in December of 1937, with a wooden turret. In about a year, the tank received a real turret, and was sent to Aberdeen.

The T5 was protected by 25 mm thick armour, and propelled by a Continental air cooled engine, which allowed it to reach a speed of 31 mph on a highway. The armament included a 37 mm gun an several machine guns. The tank's turret and sides had openings for the crew's pistols.

In the summer of 1939, the tank was accepted under the index M2. The vehicle was produced in Rock Island.

The beginning of WWII in Europe forced the American government to reconsider their priorities for armoured forces. It was no longer a guarantee that they could sit this one out, and development of a better tank began. This resulted in the M3 tank being developed in the summer of 1940, but that is another story.

Tank technology and production, the youngest branch of military technology, has no written history. Existing publicly available works of literature are either textbooks written by middlemen or privately commissioned studies of individual issues.

Our domestic tank technology and production has a brief (12-15 years), but bright and informative history. The end result of where this path led is something we can be proud of.

Our engineers created progressive, first class vehicles, and firmly retain their hold on this lead. Our tank production is a powerful and leading branch of military production. We survived the difficult times of evacuation and organization of new tank, hull, and engine factories. Our workers hold the experience of creating new types of tanks and engines, organizing mass production, lessons from life.

This rich experience that we gathered over the years is easy to lose. Additionally, many things need to be critically analyzed to extract lessons from previous work so we do not repeat the mistakes we made.

The People's Commissariat of Tank Production considers it necessary to urgently gather all materials regarding Soviet tank building and write a book titled "Tanks and Production in the Soviet Union" in two volumes, 40-50 printer's sheets each. The first volume would be titled "Tanks" and the second "Tank Production".

Briefly, the goal of the book would be as follows:

The book is classified, with a limited run (100-200 units), meant for senior staff of tank production.

The book must summarize the many years of rich experience of domestic tank technology and experience of setting up a powerful manufacturing base, as well as critically analyze this experience.

The book must not just be a chronological record of events and a set of descriptions of designs, but must also be filled with a large amount of statistical materials.

The book must illustrate the role of comrade Stalin in the creation of leading tank technologies and tank manufacturing.

The book must illustrate and criticize our mistakes and drawbacks (especially in the period of the Patriotic War), both in the process of tank design and development of tank production.

The book needs to carefully investigate and evaluate Soviet tank technology, original solutions, and technical supremacy.

The book must illustrate the race in tank technology between us and fascist Germany and our victory.

Demonstrate the advantages for the army and factories of releasing a limited amount of tank types compared to the many types used by our enemies and, especially, our allies.

Illustrate the role of artillery engineers in the process of designing powerful tank guns and the close cooperation between tank and artillery engineers.

Remark on the superiority of our armament over the armament of our allies and enemies (large calibers).

Remark that the armour of our tanks remained at the top of scientific progress, the hull of the T-34 was a perfect specimen, that our allies and enemies strived to replicate. Describe the history of hull production.

Demonstrate the enormous scale of development of tank production after the start of the Patriotic War, especially that no country aside from ours had such a well organized structure.

Show the basis (leading machinery-building factories) and conditions of fast development of tank production in the period of the Patriotic War (leading production technology, prior experience, human resources, help from the entire country).

Illustrate in detail the issues of evacuation of tank factories, and its creation and development in the East (show organization and partitioning of tank production).

Show that tank factories were created as powerful self-reliant factories without significant cooperation (conditions in our country: large spaces, weak transportation network, etc).

Show the connection between tank manufacturing and the army, the study of tank experience in combat, and the influence on tank design and on numeric ratios of tanks.

Discuss restoration of destroyed factories.

Show the role of subcontractors in tank production, especially armour, electronics, rubber, ball bearings, and artillery.

Show the role of tank production in equipping the army with spare parts and organizing repairs.

Show the future of development of tank technology and manufacturing in our country.

The People's Commissariat hopes that its proposal will be met with support at the factories, and proposes the following order of work:

Each factory creates an editing committee of 5-7 people, consisting of the editor-in-chief (factory director), chief engineer, chief designer, and two or three more engineering or technical workers from the factory, at the director's decision. Inform the People's Commissariat of the composition of this committee.

Each factory writes a book about themselves following the plan above.

As each chapter is written, it is sent to the People's Commissariat.

All material must be sent to the editor's office no later than July 1st of this year.

Proposed time for sending the book to print: 4th quarter of 1945.

The People's Commissariat is certain that factories will actively take up this task and the result will be a useful and interesting book.

Thursday, 25 February 2016

On the condition of the KV-13 as of September 30th, 1942, I report that:

On September 26th, the first factory trial began, a 20 km march. All components of the transmission and suspension worked well. Oil pressure dropped to 2 atm. as engine RPM increased due to a defect in the oil reductor valve. The defect was corrected after the trial.

On September 27th, a second trial was scheduled, a 25 km march. The following defects were discovered:

Worsening of the gearbox actuator on the 30th kilometer.

Three road wheel hubcaps were lost.

The water in the cooling system is hot, reaching 110-115 degrees with a temperature of 10-12 degrees outside.

Controlling the tank is difficult.

The engine does not increase RPM in 9th gear and works poorly.

All other tank mechanisms worked satisfactorily.

An M-1 car following the tank was used to gauge its speed. At 1800 RPM in 9th gear, the tank runs at 55 kph. This is almost the same as the estimated top speed (57.6 kph using a T-34 track).

Examinations after the trial showed the following:

The loss of hubcaps was caused by a design defect in the ball bearing in the wheel axle. The wheel could move along the axle relative to the ball bearings and hit against the hubcap. Not able to withstand the force, the hubcap bolts were torn off and the hubcap fell off and got lost. The design of the ball bearing in the wheel axle is being urgently reworked.

The gearbox actuator worsened due to a knocked off calibration of the main clutch. It was discovered that it is not possible to calibrate the main clutch without removing the radiator.

Difficulty in controlling the tank can be explained by necessary force of 60 kg on the levers and 90 kg on the main clutch pedal. The servo mechanism of the main clutch works poorly. The design of the controls is being urgently reworked.

The hand gas lever does not allow the third position of the multiplexor lever to be used.

The tachometer panel hits the driver's hand when the right lever is pulled to the maximum.

The air filter cannot be removed for cleaning without removing the oil radiators.

The turret travel lock disengages during movement.

The locks on the firing ports are unusable.

The track tightening mechanism travel is short and does not sufficiently tighten the tracks.

The balancer is attached weakly and can be turned.

Aside from the above, many small and easily correctable defects were discovered.

Most defects discovered during assembly, trials, and inspection after trials are corrected. Designers are making new blueprints with corrections to the tank's weaker points.

The tank should be disassembled for improvements and corrections of discovered defects.

Wednesday, 24 February 2016

People have complained about how Front or Army level documents sometimes lack the amount of detail they want. The harsh reality of war is that the Front or Army HQ is usually in a much safer place than, say, the Brigade HQ.

Aforementioned documents from the 50th and 51st Tank Brigades burned up with the tanks of the chiefs of staff, parts of the 51st Tank Brigade documents disappeared along with the operations department secretary. Documents from the 57th Motorized Infantry Brigade burned up along with the HQ tank during a bombing raid.

Tuesday, 23 February 2016

"To the Deputy Chief of GABTU, Major General of the Technical Forces, comrade Lebedev
Moscow, 2nd NKO Building

RE: reviews of the ZiS-30 SPG

In July-August of 1941, factory #92 developed a prototype and built 100 57 mm AT SPGs on the Komsomolets artillery tractor chassis, indexed ZIS-30.

All of these SPGs were sent as anti-tank guns to tank brigades, namely:

10th TBr: 4 vehicles, received on September 22nd, 1941

11th TBr: 8 vehicles, received on September 30th, 1941

12th TBr: 4 vehicles, received on September 22nd, 1941

13th TBr: 4 vehicles, received on September 22nd, 1941

14th TBr: 4 vehicles, received on September 22nd, 1941

15th TBr: 4 vehicles, received on September 22nd, 1941

16th TBr: 4 vehicles, received on September 22nd, 1941

18th TBr: 8 vehicles, received on October 3rd, 1941

19th TBr: 8 vehicles, received on October 5th, 1941

20th TBr: 8 vehicles, received on October 7th, 1941

21st TBr: 8 vehicles, received on October 11th, 1941

22nd TBr: 8 vehicles, received on October 7th, 1941

23rd TBr: 8 vehicles, received on October 9th, 1941

27th TBr: 8 vehicles, received on October 13th, 1941

38th Motorcycle Regiment: 4 vehicles on September 22nd, 1941

GAU still has no information on the performance of these SPGs.

I ask you to order the commanders of the aforementioned units to provide by March 10th of this year comments on the performance of the 57 mm AT SPG and its tactical use, as well as requests regarding further development of SPGs.

Deputy Chief of GAU and Chair of the Artillery Committee, Major-General of Artillery Hohlov

Monday, 22 February 2016

"Interrogation record of a German army prisoner, Gefreiter Arthur Fantull from 7th Company, 2nd Battalion, 64th Motorized Regiment 16th Tank Division captured on November 18th, 1941 in Grevtsovo.

1. General data about the prisoner

Prisoner of war Arthur Fantull was born in 1921 in Hessen. Education: 6 grades of public school. Profession: worker, quarrier. His father was a worker at a printing press. Currently his father is retired. His father's age is 67.

The prisoner was drafted into the army in April of 1940. He was sent to Isalon, to 3rd Company, 4th Reserve Battalion. After finishing training in October of 1940, he was transferred to the 64th Motorized Regiment.

The prisoner was captured on November 18th, 1941, under the following circumstances: the regiment moved to a new place, 4 sick men were left in Grevtsovo, but Russians came instead and captured them.

2. The division's objective

Initially, the division was tasked with taking Odessa, but then that objective was cancelled and a new one was given, to capture Vatum. After, a more specific task was given: capture Shakhty, Novocherkassk, go around Rostov from the north, surround it, then move south-east and capture Maikop.

According to the prisoner, the 14th TD and SS regiment "Adolph Hitler" fights on the right flank of the 16th TD, mountain infantry is on the left (the prisoner does not know which unit).

3. Organization of the 16th Tank Division

Two motorized infantry regiments are included in the division (64th and 79th) as well as one tank regiment (2nd).

The 64th Motorized Regiment consists of two battalions and one artillery company. The first battalion includes 1st, 2nd, 3rd, 4th, and 5th companies. 1st, 2nd, 3rd, 6th, and 7th companies are motorized infantry, 8th company is armoured cars, 4th and 9th are heavy weapons companies, and 5th and 10th are engineers (now disbanded due to heavy casualties).

Infantry companies consist of three infantry platoons. Each platoon has three squads, three infantry and one strike.

The 10th Engineering Company is almost entirely destroyed. It used to have 50% engineers and 50% artillerymen.

The 11th Independent Company has two 150 mm guns and is acting alongside 10th Company under orders from the battalion commander.

4. Armament

The 16th TD has 50 tanks (instead of 250 authorized)

T-1: armed with two machineguns.

T-2: armed with two machineguns and one 37 mm gun.

T-3: armed with two machineguns and one 50 mm gun.

T-4: armed with two machineguns and one 75 mm gun. This tank weighs 32 tons.

Composition of the 2nd battalion: (list given)

Each infantry platoon has three infantry squads and one strike squad. Each infantry squad has two machineguns. The strike squad has no machineguns, but each soldier has more grenades than an infantry squad soldier. Each NCO has a submachinegun. The squad also has 2 heavy 10-round rifles and 3 light 47 mm mortars.

8th Company has 15 special armoured cars armed with a total of 28 heavy machineguns and 2 37 mm guns.

9th Company has 8 heavy machineguns and 8 heavy mortars.

10th Company has AT and infantry cannons, the prisoner does not know how many.

11th Independent Company has 2 150 mm infantry cannons.

The first battalion differs from the second in that it does not have a special armoured car company, but instead three infantry companies.

5. Weapon losses

Losses of small arms are constantly replenished, and the prisoner estimates that it is currently at authorized strength.

6 special armoured cars from the 8th Company have been destroyed. 9th Company lost 50% of its weapons. One AT gun broke in 10th Company. There were 24 cars at the start of the war, now there are only 12.

6. Company of special armoured cars

This is the only experimental company in the division, the so called armoured infantry, designed for cooperation with tanks. The company had 15 armoured cars, with only 9 remaining. The armoured cars are open on top, and only the driver and the sides are protected with armour. The car has four axles. The first two wheels are normal. The other three pairs are on tracks. The tracks are weaker than tank tracks, but do not make as much noise as tank tracks.

The armoured car is armed with two machineguns, one in the front and one in the rear, or a 37 mm gun in the front and a machinegun in the rear. Additionally, 4 mortars are installed on the sides. These mortars can only fire once per mission. The weight of one round is 100 kg. The range of the shockwave is 200 meters. The weapon is fired directly at the target. The armoured car stops to fire. A flying shell emits a whistling noise and you can see a trail (it's possible that this is a rocket). At 2000 meters, the trajectory is 200 meters high.

These weapons are only fired at large concentrations of personnel at the orders of superior commanders. These mortars were used at Nikolayev, where 9 vehicles (36 launchers) made 36 shots.

Each vehicle is serviced by 7-8 soldiers. The machineguns can fire on the move.

Word in the regiment is that every company will receive these armoured cars. The difference is that the new cars will have regular light mortars.

7. Personnel strength and losses

A company's authorized strength is 180 men. In actuality, 6th Company has 120 men, 7th Company only has 80 men. 8th Company has heavy losses. 9th Company is taking heavy losses, as almost all reinforcements are sent to this company. 10th Company lost almost all engineers.

8. Reinforcements

Over the war, the 2nd Battalion received reinforcements 4 times. The first time, 80 men were sent as reinforcements at Uman from the reserve battalion (young men, many of them volunteers). The second time was 30 men from destroyed units. The third time, reinforcements came from Konstant (80 men). These were also young men, but all of them were drafted, there were no volunteers. The fourth time the battalion received 20 men from destroyed units. In total, the battalion received 210 men. Currently, no reinforcements are expected.

9. Preparations for winter

Preparation of vehicles includes preparing straw mats to cover the engines and issuing Glizantin for antifreeze, which prevents freezing until -12 degrees.

Cars are in poor condition, Captured cars are used, but there are currently few.

There is no non-freezing grease for either weapons or vehicles.

10. Supplies

Lately, fuel comes very irregularly. Infantry is often unable to use cars due to a lack of fuel. The explanation for the lack of fuel is that it's being sent to the Moscow front.

There is no winter equipment. The excuse for southern forces is that it is warm. The prisoner heard that there will be no winter equipment from the regimental intendant.

No food has come in over the last 14 days. The company is feeding itself at the cost of the local population. Soldiers receive about 400 grams of bread per day, sometimes it is possible to "obtain" a pig, and then his squad gets raw meat. The soldiers must prepare their own food. The food issued by the company is insufficient, and soldiers are "forced to display personal initiative". "Personal initiative" is forbidden, but the prisoner does not know a single case where anyone was punished for it.

11. Preparations for chemical warfare

The prisoner did not hear anything about chemical warfare. Every soldier has a gas mask, but they were only carried for the first two weeks of the war, after that they were left in trucks.

12. Moral and political condition

The officers told soldiers that Germany needs the Ukraine, needs wheat and oil. The Russians must go away to Siberia. They are told that the Russian army no longer exists. Soldiers laugh at these claims and ask each other: if the Russian army no longer exists, why do we not advance, why is there no gas or winter equipment?

Soldiers receive bad news from home. The news say that the people are tired and waits for a quick end to the war.

13. Miscellaneous

The prisoner says that they are not going to receive winter equipment and reinforcements as Kleist's group is heavily beaten and will be replaced by elements of List's group, which allegedly arrived from Bulgaria. It will still be called Kleist's group.

16th TD was supposed to be transferred to Guderian's group to the Moscow front, but since it was so weak, the 9th TD was sent instead.

The prisoner heard that 15-25 new tank divisions were formed in Alsace.

Interrogation by:

Intendant 3rd grade Schlosser

Junior Lieutenant Isadchenko

Information department of the South Front HQ, Major Trusov

December 4th, 1941"

Two items of interest. One is the confusion of the PzII for some tank with two machineguns and a 37 mm gun, likely a Pz38(t) or Pz35(t). The other, a lot more interesting, is this "special armoured car". Clearly, it is a halftrack with "Stuka zu Fuss" rockets on the sides, but the word "halftrack" was not common in those days, so presumably the translator had to explain it as best he could.

Sunday, 21 February 2016

The British post-war FV4202 medium tank never entered mass production, and its run was limited to three units. One of them was scrapped and another converted to an ARV. The third became an exhibit at Bovington. So what's the history of this vehicle?

Towards the mid-1950s, tank designers saw that the current generation of tanks is at an end. Something new and revolutionary had to be done. The 1950s, specifically the latter half, became a time of new creative ideas in the tank design world.

The birthplace of tanks was no exception. The Centurion, the peak of the achievements of British engineers during WWII, was nearing its decline. Three roads were open: one was the creation of a while new tank, another was a deep modernization, the third was an evolutionary step. The third path was seen as the least promising, but it was the one that was chosen. The 105 mm L7 gun's appearance extended the Centurion's life for decades. Even the prototype built in 1945 was still serving somewhere. The result of this modernization was the Centurion Action X that appeared in 1955. The Centurion Mk.7 hull was equipped with a new turret, but the project did not progress past experiments.

As for the creation of a new tank, the first step in this direction was taken in 1956. A tank nicknamed "40 ton Centurion" entered trials. This was an unofficial nickname, of course, the tank's real index was FV4202. Compared with the competitor Medium Gun Tank FV4201, it seemed like a step back. The "predecessor" had an IS-3-like pike with a central position for the driver, and a whole new turret. The FV4202, the vehicle chosen to be built in metal, was a much more conservative evolution of the ideas in the Centurion and Centurion Action X.

The hull was a development of the Centurion, but ended up somewhat lower. Thanks to this, the overall height of the FV4202 was 2.75 meters, a whole quarter of a meter less than the Centurion. The lower hull was used to increase the slant of the upper front plate. The hull was also half a meter shorter, reducing the amount of road wheels to five per side. Thanks to these operations, the mass of the tank decreased from 51 to 40 tons.

The turret was a development of the Action X. The front resembled its predecessor, but had some novelties, like the "beard" underneath the gun mount. The roof also had many common elements. The rear was noticeably different. A late model 20-pounder gun was used. By this time, it got rid of the massive muzzle brake and obtained a fume extractor. Externally, this gun looks similar to the 105 mm L7, which leads to confusion.

Three FV4202s were built. Trials continued for several years, but the tank wasn't given a chance. The evolutionary development of the Centurion was declined and, instead, the FV4201 concept was developed further. By September of 1959, the P1 prototype entered trials, leading to the Chieftain tank family.

One of the FV4202 prototypes was sent to the scrapyard. Another was converted to an ARV, which can be seen in the REME Museum of Technology. The third vehicle ended up in Bovington. Time and a harsh climate did their thing, and the vehicle currently requires a very thorough restoration. Several years ago, the Vehicle Conservation Center was built, which now houses several vehicles that used to be outside, including the FV4202. There is hope that, someday, skilled hands will find their way to this tank, which was a significant, if not well known, point in tank development. Who knows that British tanks would look like if the British would adopt a vehicle that was much smaller than the Centurion, yet equal in protection and firepower.

Let's take a closer look at the tank.

The tank did not survive to this day in a good shape. The armour skirts, similar to those on the Centurion, are gone, as are much of the fenders. Instead of its own tracks, the tank wears those from late Centurion models. A lot of the stowed equipment is gone, including the headlights and tools. Nevertheless, this is much better than a scrapped tank, but the restoration crews have their work cut out for them.

Despite many similarities, the FV4202's hull differs from that of the Centurion. Most notably, the hull is lower to the ground, allowing the front armour to be placed at a sharper angle. With the same armour thickness, the tank is much better protected than the Centurion, although 80 mm of armour in the late 1950s was not enough, even with this slope.

Like the Centurion, the FV4202's driver is positioned to the right of the tank's axis. The reduction in size did not do wonders for the comfort level, but recall that the Chieftain's driver is practically lying down. Here, the workspace is still more or less acceptable. Unlike the Centurion's two piece hatch, the FV4202's driver hatch lifts and rotates to the side. This is a much more convenient solution.

The suspension migrated from the Centurion Mk.5 with nearly no changes. Of course, "nearly" has a number of nuances. First, the amount of road wheels was reduced to 5. Second, the width of the track links decreased. The tank lost its original tracks, so the second difference is currently gone.

The FV4202 used Horstmann's suspension, which, in various forms, was used on British tanks since 1922. This design was last used on the Chieftain. Despite this rather conservative design, this suspension was satisfactory. However, the issue of removing the bogey in combat conditions was a difficult one.

The rear is similar to the Centurion. Nothing is revolutionary here, just a standard vertical plate. To the left, one can see a field telephone that has been ravaged by vandals, a typical feature on post-war British tanks.

The engine compartment roof is also similar to the Centurion's. One of its features is a multi-part design. This is a very convenient system, even a person without great physical strength can open up the engine compartment on their own. The Americans used a similar system on the Pershing and the Patton, and the Swiss used it on the Panzer 61.

The bottom of British tanks is the pinnacle of minimalism. No hatches here, only a few service openings. If the tank was knocked out, the crew would have to leave under enemy fire.

The turret of the FV4202 has much in common with the Centurion Action X, especially the front. However, there are a series of differences. For example, a "beard" under the gun mantlet, protecting the turret from jamming.

The main armament of the FV4202 is a late model 20-pounder gun. It lacks a muzzle brake, but has a fume extractor to extract gases after firing a shell. From far away, this gun looks like the L7, but close up one can see that the fume extractor shape is different.

From the top, one can see that the FV4202 turret is a combination of technical solutions. The front of the turret is similar to the Centurion Action X, and the rear is more like a regular Centurion. The roof is closer to the Action X.

Saturday, 20 February 2016

The phrase "I'll be back" gained popularity many years before the Terminator movie hit theatres. In 1942, it was spoken by Douglas MacArthur, the commander of the Philippine defenses, after breaking through to Australia on a torpedo boat. He and his forces did not hold back the Japanese and were forced to retreat. On October 20th, 1944, he walked off a landing ship onto the Philippine island of Leyte, shoulder to shoulder with his soldiers. Slowly but surely, island after island, the Japanese invaders were squeezed out of the archipelago.

On January 9th, 1945, American forces landed in Luzon, the main island. The prelude to the battle for the capital, Manila, has begun.

Tanks in Luzon, Japanese View
Yoshiharu Iwanaka's 2nd Tank Division was ready to meed the Americans in the Philippines. It contained about 200 tanks, mostly Type 97 Chi-Ha and Shinhoto Chi-Ha, but also a few light Type 95 Ha-Go and obsolete Type 89s. In October of 1944, the division lost two tank companies (about 30 vehicles) which were sent to Leyte to defend against the American invasion.

The commander of the Japanese defenses of the Philippines, Tomoyuki Yamashita, understood that defending against the American invasion is an unrealistic task. However, he planned on lasting as long as possible to allow the main forces to retreat into the mountains, where dealing with them would be much more difficult.

On January 16th, Yamashita ordered the 7th Tank Regiment to attack the American foothold. The order was supposed to be carried out by a tank company and a motorized infantry battalion. Moving out at night, they were caught in an anti-tank gun ambush and suffered serious losses. In the morning, the Americans attacked themselves, targeting the main forces of the Japanese regiment, quartered in a small city called Urdaneta. In this battle, only one Japanese tank platoon had any luck, taking up favourable positions and knocking out two Shermans before they were knocked out in return. The other Japanese tankers had no such luck; their 47 mm shells could only penetrate a Sherman in the sides and rear.

The remainder of the 7th Regiment (34 tanks out of 60 authorized) retreated to San Manuel. The Americans were not in a hurry to attack them. Instead, they spent five days grinding Japanese defenses into dust with bombs and artillery. The Shermans only attacked on the dawn of January 26th. One by one, they shot up the Japanese tanks from a safe distance. By the evening, the regiment shrank to 7 tanks, the crews of which carried out the Japanese tradition in an unescapable situation and launched a suicide attack.

Unlike them, the commander of the Japanese 10th Tank Regiment had a much more "European" idea, ordering his crews to abandon their tanks and fight their way back to their main force on foot.

The 6th Tank Regiment, located in the southern part of Luzon on the day of the landing, moved out north and quartered themselves in the town of Munoz. The tankers defended against their first attack on January 27th. American infantry fell back once they encountered resistance, but aircraft started their hunt for Japanese tanks. The second attack, this time with the use of Shermans, started on January 30th. As a result, the city was completely surrounded and the Japanese regiment had only 20 tanks left. The order to retreat was only given a week later. At night, the surviving Japanese soldiers fought their way out through a storm of American fire, with only one in five making it out alive.

In this battle, the Japanese faced C Company from the 44th Tank Battalion. The "Tank News" newspaper of the 6th Army called it "the hottest tank on tank battle in the Pacific". American soldier had to not only shoot, but fight hand to hand. In the morning, the Americans discovered 10 knocked out tanks in front of their positions, one light tank, a couple of trucks, an all terrain vehicle, and 245 dead Japanese soldiers. C Company got off with one killed, 11 wounded, and 2 damaged tanks.

The last tank battle in Luzon happened in April of 1945. The attacking Americans were nearing the HQ of the 14th Japanese Army in Baguio. At that point, General Yamashita only had three medium and two light tanks left from the 5th Company of the 10th Regiment. Since they had no chance of dealing with the Americans in open battle, Yamashita ordered a suicide attack, attaching explosives to the front armour of one medium and one light tank. According to Japanese records, they managed to burn up two Shermans in that fight, and crews of knocked out Japanese tanks left their vehicles and rushed at the enemy, swinging their swords.

Battle for Manila, American View
The Americans knew that the Philippines held a large amount (for the Pacific theatre, anyway) of tanks. To be safe, American units were reinforced with not only Sherman battalions, but tank destroyed battalions armed with M10 Wolverines. It's worth noting that the Wolverines were excessive: the weak armour of Japanese tanks could be penetrated by regular Sherman guns without effort.

A Japanese report recorded how an American AP shell fully penetrated a Japanese tank and blew up in the mud 20 meters behind it. American anti-tank gunners noted that Japanese armour can be penetrated by HE shells and that this causes much more destruction inside the tank. The majority of shells used by the anti-tankers were HE, AP shells were only used in the Philippines a few times, when shooting at caves or pillboxes. The losses of the AT crews were negligible, one M10 drowned in a river, one was damaged by a mine, and another few suffered negligible damage as a result of Japanese pole mines.

One of the priority tasks for MacArthur's troops was the taking of Manila. The general expected that this would minimize the casualties among the city's civilian population and American prisoners of war that were held in the capital. In addition, the liberation of Manila was supposed to encourage the Philippinos to more actively resist the Japanese, especially since the previous few years gave them more than enough reasons for hatred.

Interestingly enough, Yamashita wanted to give up Manila as much as MacArthur wanted to take it. He considered the city a trap and its defense a waste of already diminishing resources. He may have had his way, if not for a peculiarity of Japanese warfare. The Navy always looked down on the Army, and the commander of the Manila defenses was Rear Admiral Sanji Iwabuchi, former commander of the battleship Kirishima that was sunk by the Americans in 1942. He decided to restore his honour for his lost ship and die a samurai's death. In order to do this, the city must be defended, and not abandoned on the order of some Army man.

According to some sources, Iwabuchi had about 4000 soldiers that fell behind their land units and 15,000 poorly organized sailors with no land experience at his disposal. The Rear Admiral also had a single tank, an American M3 Stuart that was captured when Manila was taken in January of 1942. These were the forces that Iwabuchi was going to use to defend the city, to the last Japanese, American, or Philippino, whichever came first.

Three tank battalions participated in the battle for Manila at first (711th, 754th, and the aforementioned 44th), as well as a tank destroyer battalion. The "flying column" of tankers from the 44th Battalion managed to carry out MacArthur's orders and penetrate the Japanese defenses, reaching the University of Santo Thomas building by February 3rd, which housed nearly 4000 prisoners of war.

Then the clearing out of the city began. This was done with the forces of the 37th Infantry Division with support of tanks from the 44th and 754th battalions. The history of the latter contains the phrase "This was a new type of fighting for tanks and infantry. Tanks were used as mobile artillery in a very limited space."

Japanese mines made a lot of trouble for the Americans. Despite all of engineers' efforts, tanks blew up on streets that were allegedly cleared of mines.

On February 7th, one of the American tankers wrote in his journal: "Manila is on fire". Houses were burning as well as tanks; the attempt of two platoons from the 44th Battalion to move forward ended tragically. The Japanese attacked the tanks with 20 mm and 125 mm naval guns, as well as grenadiers carrying mines and Molotov cocktails. Three Shermans burned up, two more were damaged. Other American units also reported suicide attacks with Molotov cocktails. Another tank received three hits from a 5 inch gun. The Sherman's armour could not withstand such a caliber and the tank was completely destroyed. 4 tankers died.

To protect the 800,000 civilians in Manila from excess deaths, MacArthur implemented harsh restrictions on American artillery and air support. This did not have the desired effect. By the end of the battle, the city lay in ruins.

On February 13th, 1945, the Americans reached the old city. Its thick stone walls were immune to 75 mm shells. One of the most resilient buildings was the police station: it cost the 754th Battalion several days and three lost tanks. Another memorable structure was the building known in Manila as the "German house". After an extensive shelling, tanks and infantry tried to get close to it, only to have one Sherman be knocked out by a mine and pelted with Molotov cocktails.

The battle for Manila ended on March 3rd, 1945. 1010 American soldiers died in the battle, and almost 5600 were wounded. The Japanese lost about 16,000 men. The Americans ended up re-capturing that one single M3 that Iwabuchi had at his disposal.

Friday, 19 February 2016

The creation of the AMX ELC 90 for French airborne units reflected post-war France's desire to return to the superpowers club. The enormous colonial empire of the Fourth Republic was splitting at the seams, and the creation of highly mobile and well armed airborne forces was a pressing issue for the French army. What stopped this tank from entering mass production?

The first attempt at an airborne tank was made right after the war. In November of 1946, a 12 ton tank project was completed, armed with a 75 mm gun. The tank never got its wings, but further evolution of this design culminated with the AMX 13, the first truly mass produced French post-war tank, which is still in service in some countries.

The next attempt at an airborne tank came almost 10 years later. In 1954, the Engin Léger de Combat (light fighting machine) program was launched to create a 6 ton tank, or rather a tank destroyer. Two companies made a bid for the ELC tender, Ateliers de construction d'Issy-les-Moulineaux (AMX), a part of the DEFA conglomerate (later GIAT, now Nexter) and Brunon-Vallette (EVEN) from Rive-de-Gier, a small town south-west of Leon. Both companies made unusual vehicles, worthy of their own articles.

AMX's engineers used the Hotchkiss CC-2 APC as their base, making their tank a relative of the German Spahpanzer SP 1C, created on the same basis. Indexed Chenillette 4–120SR, the AMX project was initially envisioned as a rather unusual design, similar to the American M50 Ontos. Presented in March of 1954, it was a two-seater vehicle armed with four 120 mm recoilless rifles. AMX engineers didn't move this idea past paper, unlike EVEN ones, who made a similar vehicle.

Another project was proposed in July of 1954, the Chenillette 6–105SR. The vehicle was radically redesigned and the armament was changed to six 105 mm recoilless rifles. In both projects, the driver was positioned forward and the turret rotated fully. This design also did not progress further than paper.

The hero of this piece was first drawn on April 27th, 1954. The project was first called Chenillette biplace avec casemate tournante de 90 (two-seater tankette, 90 mm gun in a casemate turret) and had both crew members in the turret. On one hand, this simplified the layout. The engine was placed in the front, which made the vehicle very compact.

On the other hand, this created a ton of problems. The turret could only rotate fully if the vehicle was still. The turret could not rotate on the move, as the driver would lose access to his controls and observation devices. In an attempt to solve this problem, the driver was moved to a cockpit to the right of the tank's center. To achieve this, the engine and transmission were moved to the rear, and the turret moved to the front.

The driver would only inhabit his cockpit during battle. On the march, he remained in the turret. However, the battle conditions were so inhumane that AMX returned to their original idea. Interestingly enough, EVEN engineers managed to house their driver in this fashion.

The first AMX ELC 90 prototype started trials in 1955. Instead of a tank destroyer, it was a tank, a curious tank, but a tank nonetheless. The vehicle received a 90 mm D915 gun in a two-seater TC 910 turret developed by FAHM (Forges et Aciéries de la Marine et d'Homécourt). After two years of trials the AMX ELC 90 bis came to be.

The vehicle differed noticeably from the prototype. The tank was equipped with roof-mounted smoke grenade launchers. The observation devices were redesigned, and the gun mantlet changed. The engine compartment roof and upper front plate changed, as well as the fenders and the equipment mounted on them. The amount of road wheels grew to five.

Trials continued until 1961 when the Engin Léger de Combat program was cancelled. The French army never received its airborne tank, even though the AMX ELC 90 bis was far from the worst tank for the role. Of course, it had its problems, mainly with maneuverability of fire and convenience for the driver, but it was very appropriate for certain tasks. Finally, the even weirder M50 Ontos was not only produced, but actually fought.

Both AMX ELC 90 prototypes survive to this day, but the fate of the first one is shaky. It was last seen in the forested storage yard of the Saumur tank museum in the mid-1980s. It's most likely still there, but there are no photos confirming the fact. As for the AMX ELC 90 bis, it was much luckier. It stands as one of the central exhibits in a room dedicated to unusual post-war designs.

Thursday, 18 February 2016

In 1941, the Red Army found itself desperately struggling to fill a shortage of small caliber anti-tank artillery. While anti-tank rifles were still on the drawing board, improvisations like these had to be made.

"Decree by the Military Council of the Northern Front #187ss
Leningrad
August 22nd, 1941

Contents: on the end of DOT-4 production and production of simplified ant-tank guns on a wheeled mount at factory #7

Wednesday, 17 February 2016

"February 27th, 1942
To the Chair of the Artillery Committee, Major General of Artillery Hohlov

RE: Modernization of the 45 mm mod. 1937 anti-tank gun

Considering the importance of this task, Molotov factory #172 immediately began the modernization of the 45 mm mod. 1937 AT gun according to specifications in letter #567079 sent on February 4th, 1942.

The modernizations proposed by the factory based on the requirements attached to letter #567079 are as follows:

The upper and lower mounts are changed slightly in connection with the changes made to the screw type turning mechanism.

The recoil brake is unchanged. The trails remain unchanged as well.

Currently, blueprints for the barrel, breech block, and breech are ready and the parts are being machined. According to the factory schedule, trials will start on April 1st of this year.

At the same time as this modernization work is being done, the NKVD Special Design Bureau is working on a modernization design that only replaces the barrel, keeping the existing breech block and semiautomatic mechanisms, with the aim of being able to replace the barrels on already existing gun mounts.

The NKVD 45 mm mod. 1937 AT gun modernization project is as follows:

Increase of the barrel length by 27.5 calibers compared to the existing length.

Robustness category of 0-80.

Increase of the gunpowder charge by 35 grams.

Maximum chamber pressure of 3100 kg/cm^2.

Propellant density of 0.76.

Minimum robustness reserve of 1.18.

Muzzle velocity of 920 m/s.

Penetration of 54 mm of K=2400 armour at 30 degrees at a range of 400 meters.

Due to the lengthening of the barrel by 27.5 calibers, the center of gravity is moved by 150 mm and the breech is made heavier to compensate for this unbalance. In order to maintain connection to the semiautomatic mechanism, which is not altered or moved, the semiautomatic rod (part 02-43) is lengthened to the necessary size.

Due to the change in the center of gravity, the maximum gun elevation is reduced from 25 degrees to 21 degrees 40 minutes.

Factory trials of the NKVD variant are planned for March 10th of this year.

Comparing the two variants, the second variant provides a quick solution for the issue of increasing the strength of our gun. Connecting this issue to production numbers, the Molotov factory variant promises to reduce the amount of machinery hours from 550 to 250 per unit (according to preliminary calculations) due to a modernized mount.

The overall issue, increasing power and increasing the amount of units built, is better solved by using the NKVD barrel and Molotov factory mount.

Monday, 15 February 2016

"To the Deputy People's Commissar of Defense, Marshal of Artillery, comrade Voronov
To the Chief of GAU, Colonel-General of Artillery, comrade Yakovlev

The faculty of artillery armament at the Dzerzhinskiy Order of Lenin Academy developed a design and an experimental prototype of two types of 25 mm semiautomatic AT guns (main author of the project is Engineer-Lieutenant-Colonel comrade Sidorenko). Work began in April of 1942 but due to a lack of materials and difficulty of production in Middle Asia, was only finished in January of 1943.

The prototype is worthy of attention for the following reasons. After the project began, information about the German 28/20 mm caliber AT rifle was acquired. The designed prototype is close to this rifle in its specifications, but is significantly more powerful. A comparison of the two systems follows.

Artillery Academy

German AT rifle

Caliber

25 mm

20 mm

Shell mass

0.295 kg

0.122 kg

Muzzle velocity

1200 m/s

1368 m/s

Muzzle energy

21600 kgm

11900 kgm

Propellant mass

0.231 kg

0.152 kg

Rate of fire

16-20 RPM

12-15 RPM

Horizontal range

60 degrees

70 degrees

Time to deploy

Up to 15 seconds

25-30 seconds

Mass

[illegible]

[illegible]

Bore axis

300 mm

700/420 mm

As you can see, the system will have notably superior penetration with an almost identical weight while being easier to camouflage, with a higher rate of fire (thanks to the semi-auto mechanism) and has only slightly less agility of fire.

The ballistic data is only for the regular 25 mm sell. The author proposes a special lightened shell that would easily increase the muzzle velocity to 1500 m/s with a more powerful shell than the German rifle. Experiments showed good stability of the system.

A significant part of the semi-automatic mechanisms is built with unchanged mass production parts.

The system is simple to produce and maintain. The high muzzle velocity is also reached without the need for a conical barrel, which simplifies production.

I send two samples of the gun to Moscow for trials. The author, Engineer-Lieutenant-Colonel Sidorenko, is accompanying them.

"Based on the provided materials, preliminary conclusions can be made:

The system has the following tactical advantages compared to 76 mm and 45 mm guns:

Lower weight

Lower bore axis

Smaller crew

Sufficient penetration to combat medium and light tanks at a range of up to 600 meters

Sufficient rate of fire.

Drawbacks compared to the same guns include:

Lower penetration, necessitating the use of 76 and 45 mm guns along with this system.

[illegible]

Conclusions: conditional on the correction of design flaws revealed by trials (recoil, extraction, etc), the proposed system could be adopted to replace the 45 mm gun at the battalion or even infantry regiment level.

Sunday, 14 February 2016

Heroes of our history have a direct connection to tanks. They created them, they tested them, strengthening the Soviet military. They lived in a difficult time and withstood many trials. Some, undoubtedly, did not hold out, but Joseph Kotin and Anastasia Poklonnova were not among them.

Straight A Students
Long before the Great Patriotic War, in the early 1930s, when Soviet armoured forces were just being established, a girl enrolled in the Frunze Military Technical Academy.

Anastasia Poklonnova was first placed into the Faculty of Chemistry, but reached her goal a year later and was transferred to the Faculty of Mechanization and Motorization. It was not easy for her to keep up with the other cadets, but she tried with all her might. A badge on her blouse that read "Excellence in Tank Driving" was evidence of her success.

Many future officers liked the girl, but she responded to only one: Joseph Kotin. Handsome, a straight A student, excellent in both studies and combat, a real gentleman. It is no wonder that the young couple fell in love.

Kotin's military career began well: the graduate was personally commended by Tukhachevskiy, the commander of the Leningrad Military District at the time. Joseph started working at the Armour Academy as a military engineer and lecturer.

Anastasia finished her studies two years later. The lovers got married, but did not have time to build a family, as their duty kept them apart. Anastasia became a military representative at the Leningrad tank factory, and Joseph left for Kharkov to test a new tank. He shared his impressions by mail: "I am working on the T-35 object... The work is interesting, I have never seen anything like it. Imagine, my dear, a dreadnought climbing up on a vertical obstacle. It is a colossal sight. Every other day, I am at the trials, otherwise I am in the assembly lines."

In 1935, Kotin wrote to his wife that it is time to fly and swim. This seems like an innocent phrase, but it had a hidden meaning. Kotin was not just directing work on paratrooper and amphibious tanks, but took part in the work. That same year, the family had its first child, Felix.

In 1937, fortune shined upon the family once more. Joseph was appointed as the chief of a special design bureau at the Kirov factory, the largest tank building factory in the USSR. His job would be to design new heavy tanks. Kotin dedicated all his strength to his work.

In Illness and in Health
The fall of 1937 arrived, and luck turned from the Kotin family. Anastasia Poklonnova-Kotina was fired from the army, accused of contact with enemies of the people and sabotage. During the purge, such an accusation could have terrible consequences. Joseph Yakovlevich could not stand aside. He was not afraid to stand up for his wife even in front of Stalin himself. Kotin wrote: "Comrade Poklonnova and I have been together since 1931, and I am fully responsible for her... Mistrusting her is mistrusting me... This must be the result of misunderstanding or slander. I ask you, comrade Stalin, help me with this difficult and sensitive issue."

An emotional outburst like that could have cast suspicion on Kotin himself, but the risk was worth the reward. Anastasia Poklonnova-Kotina was cleared of all charges. The first female tanker, Military Engineer 3rd Grade, was re-commissioned by the Red Army.

Life went on. The future held more additions to the Kotin family and a difficult trial for the whole country: the Great Patriotic War when Kotin directed the creation of the KV and IS tanks. Ill-wishers spread rumours about the engineer being under Voroshilov's thumb, but history cleared all accusations. Anastasia's achievements were not only the armour and fire of her weapons, but the love and stability of the Kotin family also deserves to be remembered.

Saturday, 13 February 2016

On March 11th, 1941, Soviet intelligence reported on the production of new German heavy tanks. The largest of them, Type VII, allegedly had a mass of 90 tons and was armed with a 105 mm gun. Soviet high command took this report very seriously. Design work started to create a worthy opponent for German heavy tanks. The result of this work was the creation of several unusual projects: KV-4 and KV-5.

Fear Magnifies
The information was partially correct, as the VK 65.01 project was finished in June of 1940, and it really was indexed Pz.Kpfw. VII. One of the tanks was to be armed with a 105 mm gun, but only 20 calibers long. The design of the 36 ton VK 36.01 started in the middle of 1940, which was indexed Pz.Kpfw. VI Ausf B. This was the mass of the "Type V" mentioned in the report. Information on real vehicles ended up mixed with hearsay. This hearsay created such a stir in the Soviet Union that heavy tank designs were radically revised.

It is thought that the flywheel of superheavy tanks started spinning on April 7th, 1941, when USSR SNK and CC of the VKP(b) decree #827-345ss was issued. In reality, everything started two weeks before. Having studied the intelligence report, GAU assumed that the 90 ton tank was armed with a tank version of the 105 mm Flak 39. This gun was purchased in 1940 by a Soviet commission. Trials demonstrated that a 130 mm armour plate provided adequate defense from this gun.

On March 21st, 1941, tactical-technical requirements were composed for the tank that would be named KV-4. Its mass was estimated at 70-72 tons. The front of the hull and the entire turret would have 130 mm of armour, the sides of the hull would have 120 mm. The armament would consist of a 107 mm F-42 (ZiS-6) gun and three machineguns. A note at the end of the document said that two tanks should be made, one with a 76 mm gun (the ZiS-5 with 3-K ballistics) and one with a 107 mm gun. The tank would store 70-80 107 mm shells. A 1200 hp engine was specified as the power plant. As a temporary measure, an 850 V-2SN engine was acceptable. With the more powerful engine, the maximum speed of the tank was rated at 35 kph.

By March 27th, the draft of the decree "On the production of experimental prototypes of heavy tanks" was ready. According to it, both heavy tank prototypes were due on November 1st, 1941. The blueprints would be ready at the Kirov factory by July 17th, and Izhor factory had to have the hulls and turrets ready by October 1st. Factory #92 would deliver one 76 mm ZiS-5 and one 107 mm ZiS-6 by September 1st.

As for the engines, plans were awaited within ten days for V-2 and M-40 based designs. The V-2 was the V-2SN, but the second engine is a much more interesting proposal. This aircraft based engine was produced at the Kirov factory. Its stock power output was 1000 hp, but a supercharged 1500 hp M-40F also existed.

The sixth point in the decree contained ideas about transporting the tank by rail. The People's Commissariat of Supply Lines (NKPS) could only offer four-axle platforms with a capacity of 60 tons. Obviously, for a 70 ton tank, this was not enough.

Anyway, by April 7th, the situation changed drastically. Instead of the KV-3, a reworked T-150 with a mass of 50 tons, a new tank would be built, with the same index, a mass of 68 tons, 120 mm of front armour, and a 107 mm gun. The approach to the KV-4 changed as well. Its mass increased to 75 tons, and the armour could potentially increase to 140-150 mm. The sides thickened to 125 mm. The deadline was moved: it was now necessary to prepare the model and technical project by June 15th and the turret and hull were expected by August 15th, 1941.

This wasn't all. Instead of a KV-4 wit a 76 mm gun, decree #827-345ss instructed the Kirov factory to build a tank that would be an answer to the phantom Pz.Kpfw. VII. As the German vehicle, this KV-5 would have a mass of 90 tons. Its armament and engine would be the same as on the KV-4. The increase in mass was due to the front armour, which was 170 mm thick in the front and 150 mm thick on the sides. The crew of both tanks would be between 6 and 8 men.

According to the decree, the blueprints for this tank were due at the Izhor factory by July 15th, and full documentation with a full scale model was due on August 1st. The Kirov factory would receive a turret and a hull by October 1st, and the tank itself would be finished on November 10th, 1941.

Heavy Duty
These new requirements meant that if the tank wouldn't have to be made from scratch, the idea would have to be drastically revised. Zh.Ya. Kotin, the director of the Kirov factory design bureau, had a difficult problem that had to be solved quickly.

Zhosef Yakovlevich took the same road as the design bureau of factory #185 when developing heavy and medium tanks in the late 1930s. During development of the 115 and T-100 tanks, several variants were prepared by different groups. Kotin went one step further and included nearly all designers from the factory into the project. For extra motivation, the authors of the more successful designs would be awarded a bonus.

Work started in the middle of April of 1941. The conditions of the contest limited the engineers fairly loosely. The only constants were the engine (M-40), mass (80-100 tons) and the presence of a turret. A multi-turret layout was allowed. The main gun would be a 107 mm ZiS-6, and the military insisted on a secondary 45 mm gun. In total, 27 projects were provided for the contest. The size of this article does not permit to cover them all, so we will discuss the more interesting designs.

N.L. Dukhov was the most successful in this task. Without coming up with any excessive fantasies, Nikolai Leonidovich approached the issue conservatively and expanded the T-220 tank. The hull was somewhat lengthened and widened, increasing the number of road wheels to 8 per side. The turret was also evolutionary, resembling the T-220 turret. The T-220 also donated its commander's cupola (with some changes), equipped with a DT machinegun. The armament, a 107 mm and a 45 mm gun, was combined into a single system.

The mass of Dukhov's tank was 82 tons, the lightest of all KV-4 proposals. The armour was at the levels required by the project, and the maximum speed of the tank was on the order of 40 kph. This design won the contest.

The second place was taken by a collective design by K.I. Kuzmin, P.S. Tarapanin, and V.I. Tarotko (some sources list S.V. Mitskevich instead of Tarapanin). Kuzmin and Tarotko later proved themselves to be talented hull designers. The KV-4 tank proposed by this group was unusual. Its fighting compartment was moved to the back, and the engine was placed in the center. The main gun was placed in a casemate with a wide horizontal range. The 45 mm gun was in a separate turret. The mass of the tank was 88 kph, and the speed was estimated at 36 kph.

The third place was taken by N.V. Tseits. Nikolai Valentinovich was the most experienced designer at the Kirov factory, starting his job in the 1920s, and having a wide variety of vehicles under his belt. Tseits' design was progressive and conservative at the same time. The second gun was discarded, as he considered it unnecessary. Tseits' design is characterized by a tall turret, allowing the vertical placement of one-piece 107 mm shells. In theory, this layout would greatly ease the loader's job. In order to compensate for the tall turret, the hull was made as low as possible. A "step" separated the fighting and engine compartments.

Another project received praise, designed by A.S. Yermolayev, who proposed two variants. The first 95 ton KV-4 had two turrets. The main one had a 107 mm gun, and the second, placed in front of it, had a 45 mm gun. The second variant was the same, but the 45 mm gun turret was missing, taking 5 tons of weight with it. Yermolayev must have remembered the SMK, the development of which he was in charge of. It's worth noting that at least five other authors used the same layout as Yermolayev.

The heaviest design was by G.V. Kruchenyh, who later designed the turret for the IS-3. Like Kuzmin, Tarapanin, and Tarotko, the engine in this design was moved forward. The tank had two turrets, one on top of another. A commander's cupola with a machinegun made up the third level. Krucheniy's KV-4 weighed a whopping 107 tons. The idea of turrets stacked on top of one another came up in five other projects.

At last, let us mention the KV-4 designed by N.F. Shashmurin. Nikolai Fedorovich indexed the KV-4 and KV-5 projects "BS", which he decoded as "a madman's nonsense" (bred sumashedshevo). No one can describe what he came up with better than the man himself.

"Having received the task to design a multi-turreted cyclops among the other leading designers of the bureau, I, without the enthusiasm about that condition (just think, we just rejected the "supermarket" SMK) I made a "knight's move", rejecting turrets altogether, and doing what I once did for the KV-1, installing the M-10 howitzer in a caponier structure, a casemate. Since we just made a super-heavy KV-3 tank, I didn't think too hard about a new one. I took off the turret and repeated my previous work, a high power SPG, installing Grabin's 107 mm gun. I explained in a note that, if necessary, the gun could be removed and replaced with an infantry squad. This modification was not allowed to enter the competition, as it violated the conditions: not enough armour, mass outside the 80-100 ton range, no turrets. In order to avoid a conflict, I made a compromise. Maintaining that a superheavy cannot be a tank, I added the necessary protection, reaching about 90 tons. I kept the main gun in a casemate, but added a KV-1 turret on the roof. I.M. Zaltsmann liked the design (due to its "reasonable universality", as he called it) and I received a second place award, 1000 roubles. That was nice, I bought a fur coat for my wife."

Backup Option
On May 9th, 1941, the contest winners were annouced. Dukhov received 5000 roubles for first place. Kuzmin, Tarotko, and Mitskevich received 3000 for their second place project. Tseits, Yermolayev, and Sychev received 2000 roubles each. Shashmurin received 1500 roubles.

After that, work on the KV-4 went slowly. According to the decree, the project was due in mid June, but judging by the correspondence sent, not much progress was made towards that goal. Things got to the point that Marshall Kulik himself intervened and demanded that work speed up. No one knows how much effect that had, since his letter was dated June 12th, and the war started ten days later.

Another stakeholder, the NKPS, was doing much better. GABTU and NKPS actively exchanged mail regarding railroad platforms for new tanks since spring of 1941. The goal at first was 72 tons, but in April, the numbers changed to 80-100 tons. GABTU ordered 200 of these platforms for 1941 and 1500 for 1942. Unlike the tankers, the railroaders completed their mission. In 1941, production of six-axle 120 ton platforms began, with length and weight capacity to spare.

As for the KV-5, almost no work was done until June of 1941. According to Zaltsmann's letters, there was an idea to announce a prize for the winning KV-5 design as well, but that idea was dropped. Kotin's competition was rejected and more successful KV-4 designs were reused. As Dukhov's design was already being worked on and the front-engined tank was too progressive, Tseits' KV-4 was selected. Nikolai Valentinovich was appointed as the lead designer. Other engineers from the KV-4 contest were involved in the project: Kuzmin was designing the hull, Sychev the turret and gun mount. Fedorchuk, the most experienced designer, was given the suspension.

The KV-4 and KV-5 were in an odd place. On one hand, GABTU's position was that the KV-3, the work on which was progressing at full throttle, was a temporary solution, and would be replaced in 1942 by the KV-4 or KV-5. Which design would win would be a matter settled by competitive trials.

On the other hand, the KV-4, approved in May, had nearly no documents completed. The same could not be said for the KV-5, work on which continued even after the start of the war and the order to cease work. Even the manufacturing technology was changed. The last blueprints were dated August of 1941, when the Germans were already near Leningrad.

As mentioned above, the KV-5 was based on Tseits' KV-4. The idea of a tall turret and short hull was expanded upon and adapted to mass production. The "step" in front of the turret was removed. The driver received a personal casemate, and the hull gunner got a mini turret. Because of this, the front of the hull was only 920 mm tall. Second, the circular shape of the main turret was revised. The front armour grew to 180 mm, making it invincible to any gun of that era.

Battle of Phantoms
The development of the KV-4 and KV-5 is usually seen as a senseless waste of time and money. This is largely true. Even if the war did not start in 1941, it is doubtful that these tanks could enter mass production. However, where there's smoke, there's fire. The mistakes made by Soviet intelligence have a basis in fact.

Study of Bunderarchiv documents shows that, in March of 1941, Kripp began production of the 15 cm K. L/40 Sfl., or 149 mm self-propelled gun. In the fall of 1941, this project turned into 15 cm L L/40 fur VK 70.01. Yes, this is the very same VK 70.01, better known as Lowe or Pz.Kpfw. VII. The mass of this tank was also 90 tons, and one of the armament variants was a 105 mm gun. Perhaps this is the Pz.Kpfw. VII that intelligence discovered. In any case, this is not the VK 70.01 that is widely known now, as sloped armour was only used in Germany after the fall of 1941 when the Germans became familiar with the T-34.